The department of transportation shall assume full control and pay the costs of construction, reconstruction and maintenance of all class I highways, including bridges thereon.
RSA 230:1
1945, 188:1, part 2:1. 1950, 5:1, part 9:1, par. 2. RSA 231:1. 1981, 87:1. 1985, 402:6, I(a)(2).